Adam and Eve lived in the world by themselves, naked and without shame.
Then they both ate of the tree of which the Lord God had said they should not eat, and,
“the eyes of both of them were opened, and they knew that they were naked; and they sewed fig leaves together and made themselves coverings. And they heard the sound of the Lord God walking in the garden in the cool of the day, and Adam and his wife hid themselves from the presence of the Lord God among the trees of the garden” (Genesis 3:7–8).
The world has never been the same since. Sin seems harmless, which is why we do it, but eventually it brings shame.